Fuse for projectiles



Oct. 12, 1943. H. w. sPooNER FUSE FOR PROJECTILES Filed June 20, 1939 L 9 5 l... PHI n n 4 ZUM/f 9. mw um: J. E. DI JM. l J 1| 4 E l Z l Patented Oct. 12, 1943 FUSE Fon PnoJEc'rims Henry W. Spooner, 'Cleveland Heights, Ohio Application June 20, 1939, Serial No. 280,150

claims. (c1. 1oz- 71) 'I'his invention relates to fuses for .anti-aircraft projectiles, and particularly to that type of'projectile known as the delayed-arming, selfexploding shell, wherein there is provided, in addition to a percussion element, meansto prevent the -shell from exploding in the bore of -the gun, together with means to detonatethe 'shell somewhere near the peak of its trajectory/if -it misses its. target.

v The objects of the invention are to provide greater simplicity, through a considerable reduction in the number of parts involved-as compared with fuses of this type heretofore known; to insure ruggedness, through elimination of delicate parts; to provide increased safety in ham, dling and transportation; to permit a reduction in size and weight; to improve balance, through the distribution of the parts symmetrically about the axis; and to concentrate the weight of the parts as near the axis of the fuse as possible. Some of these features combine to insure greater accuracy in the night .of the projectile. A further object of the invention is to provide a construction adaptable to projectiles of small calibre, as well as to the larger calibres of anti-aircraft artillery.

.Two of the functions of the fuse are governed by the movement of a piston in a cylinder-this movement being controlled in part by the escape ofl uid from the cylinder. In this construction I utilize the various properties of mercury,.such asits high specic gravity, its fluid condition at all ordinary temperatures, its high surface tension, its extremely low viscosity, its ability to flow through a very small aperture when under slight pressure, its low capillarity and the fact that it does lnot wet the sides of the container.

' In the accompanying drawing, in which like numbers represent like parts in the various iigures,

Fig. 1 is an enlarged sectional View along the. axis of the fuse;

.Fig. 2 is a sectional view taken 2-2 in Fig. 1;

"2Fig. 3 is a view taken on the line 3-3 in Fig, 2, showing some parts in section and others in elevation;

' Fig. 4 is a sectional View taken on the line /l-l in 'Fig. 3;

Fig. 5` is an elevation of the piston rod;

:'Fig. 6 is a sectional view of the piston rod taken on line 6 6 in Fig. 5;

Fig. 7 is a bottom view of the under side of the fuse base.

l.In-Figs. 1 and 3 the numeral I indicates theV body of the shell, into which the housing or body 2 of the fuse is threaded. A basel 3 for supporting. the principalelements ofthe fusefis threadediinto housing 2, and base 3 is.in turn tapped` axially to receive the threaded shank of cylinder on the line base Il, which projects upward from base 3 andi is snugly fitted tocylinder 5, the lower end of which is pressed down against a flange or shoulder extending outwardly from cylinder base 4.1

The bore of cylinder 5 tapers slightly outward above-its working portion i. e., above the normal position of the working edges of piston', for the purpose of facilitating assembly, as piston 6 is vmade slightly largervin diameter than the working portionA of cylinder 5 and compressed slightly to enter it. This insures a suliiciently snugdit to prevent leakage of mercury, and to facilitate this construction, piston 6 is made-of.

slightly elastic material-such as cellulose acetate.' The upper portion of piston 6 is formed into;

a round shank l, and to this is fitted pistonvrod:

8 in the form of a cylindrical tube, which is guid-I ed in an axially placed hole in cylinder head `il, which is snugly held, as by a press fit, in the upper enlarged bore of cylinder 5.

Cylinder head 9 is provided with two diametrically opposed flanges, 9 and 9", and superim-A posed on cylinder head 9 and fastened thereto by screws II in a flangedY member Ill, with corresponding flanges I0 andIIlf, and having also two diametrically opposed ilanges I2 and I3, disposed at right angles tov flanges It and I8. Flanges I2 and I3 are drilled to form guides for two ring pins, I4 and I5 respectively; firing; pin

I4 being the percussion pin, and firing pin I5 `being controlled by the time element and hereinafter referred to as the timing pin. Both these pins are guided at their lower ends in holes provided therefor in base 3, in alignment with the guide holes in flanges I2 and I3 so that the ring pins are parallel with each other and to the axis of the'fuse, aswell as being equidistant therefrom Threaded into ilanged member Il) is a round 'tubular bushing I6, concentric with the axis of the fuse. The upper cylindrical surface of bushingv I6 acts asa guide for the lower end of a cup-shaped percussion piston Il. the upper end of whichv is guided in a cylindrical hole pro-v` vided therefor in housing 2. Piston I1 in turn acts as a guide yfor a bushing I8, which is concentrically mounted on the upper end of hollow piston rod 8, which is thus maintained in concentric axial alignment with the fuse body. A

helical extension spring I9 is secured at its lower end to bushing I 6 by means of a screw thread:

and its uppermost convolution is bent diametrically across itself so as`V to fit into notches 20 in.

moving downward by a detent ZI, provided withv a' llug .fZI' extending into piston, rodv or `tube yIl through a notch 22 shown in Fig. 5 and indicated,

normally held securely by the downward pres'- sure thereon of spring I9. Detent 2| extends b e;

2,331,633 gij tij; Y

lcylinder 5 and the bottom of groove 40.

yond the periphery of cylinder head 9 andi-ln'ter a flanged portion lll' of percussion pin ML, Vthus preventing downward movement of the percussion pin as long as the notch T21 is' fen--y gaged by the piston rod. The upper end oipercussion pin I4 is provided with a dog 2W, which forncnveni'enc'e `of construction fis -a .separa-tei partchaving la. hole into which thefzpin isfsnu'gly fitted. Dog 24' extends lon` one iside towardr bush'' ing |16 and' has. an arc-'shapedrecess that 'sure'l rounds :bushing N6 ysuiliciently 'to .prevent the do'g' froml rotating out rof: the-'path of.percussi`n pi-'sl to'n `which must engage dog 211` whenl it de-v cends. n

Timing pin Isis 'also'iprovided witna hanged' portion I5", and is noni-rally held inthe posi-tron shown by meansof a deteht 25,` which is partly. enclosedina recess in cylinder head 9 and-rotatably pivoted on apinfzt projecting 'frornithefcyflinf-A der head. Detent ext'ehds -beyond the I'pei'- riphery of cylinder head 9 and A"a portion 'cfv its` outer end is .recessed .to engage thella'nge' f fof' timing pin l5, thus preventing the .pin from descending as longy as 'detent/Z remains in 'the position shown in solid lines Fig'. 2: A Slug 25" integral with detent 25 extendsrtwardl 'the'axis4` of the fuse and' enters 'a' longitudinal slot; '21 intpiston rods, this slot havingffa'istrai'ght' vertical face 21 formed by the wallof tube 8,'and1vterminating' in a notchueprojectin'gto one side yofthemainprtion of slot 27, as' shown in Figsf* ande.v The upper end for timing pin'zlisi'iitted irlt'o a `hole provided thereforv in 'coupling 29;' ,an'df another hole in this coupling engages. tliesendlnf a'helical compression' springing which. is-:lcel-clA under 'predetermined compression in? a cylindrical space provided therefor in housing r2, theupperr convolution .of spring .-abuttingv against fa shoulder formed by enlarging:the'boreof` housing 2 'at that point; 'I'husspr'in'g 30 exerts-'a continuious downwardpressure on: timing' 'spinV 5; whichis 'prevented from descending'. byfthe detent'lZ; .A'thin sealing disc '3| is engagediby an 'annu-lar groove at the `nose 'of the. fusey'andserves to keep" out dust orioreign mai-,tery which mightimpairv the yfaction 'of the fusean'd at the same tiriie :serves-f a purpose' which will be explained hereinafter.; Two or 'more `radial holes 32',A placed iriapairs diametrically opposite leach other to preserve-bah ance; are provided in the thickerzpart: oflhousing 2; and serve as impellers to expel liartof thefairin the lower portion of' the. fuse vafter thei projectile has-been red from the'gun andfis` rotateing rapidly; I-Iole's 32 also serve as av meaIS'Or engaging a-'spanner te tighten'the thread fastenirigthe fuseto the shell.; K y 4 ,L

Immediatelybelcw the tring pills Mandi, L5. are primers 33; 33 located in,A holes. ,provided therefor in base 3, and below tire-primersare detonators 34 in the same holes.

centaine-d cylinder. e between its baseren@ piston 6 is a predeterminedA quantity forzmercury 38fwliich nearly lls the: space thus"prov1=d'e'd,.leava ing-a1 small space for air; When :theshell is-'red' the-ring in the gun, causes it to' IOtat' alt ihlh" Velocity; lbut the inertia; of tl'i' mercury wouldtend to prevent its rotation until this inertia is overcome by friction against the cylinder walls, which is inherently low. To accelerate the rotation of the mercury I provide a vane or impeller 3Q securely l chi din rvbase 4"in suclllainanrer'slt provide a small aperture 4| between the lower edge of surf/ace tension of the mercury normally prevents it frorn -erntering this groove, but as soon as su- -cient centriigugaluffqrce has been built up by the rapid rtationof the mercury caused by impeller 33:, trie; mercury fenters groove 40 and begins to escape Atl-kirough aperture 4|. At the same time th'' 'mercury takes the form of a hollowcylinder arfditsipressure .isfexertedny upward iagaifnst :piston 6. Asusoonfassuilicientpiiessureiha'szbeen thus built up' tofoyerconie:V th' downward pressureir piston' Brererted byf'springi,lppistirfirlsesvmmtil ila/'strikes cylinderhead1!s...v .'Ihismovementisfsume cient to disengagethe :wallcofe:pistolnrnidie'itrorii theznoth'in vlfig- 21| :on Jdetenfti-lzi, ev'thlchptbelfngi thus ffreed;is'acte'dauponby centriiugal'fforoeand caused to rotate into the position showninldottet n linesin Fig. 2; whelietsafn' longer firiterpsed to .prevent ldownward--1r-1ovemei11tn,ofpefrcussionpierr I-4'.' The fuse is now'anned';:andfreadyftoidetonat the' shelll if 'itvstrikesai target.` Itii's fhighlycde sifrable` that tlieziuse; be notzonly ffbullet-satei-1:-L incapable ff explodingthe sheltin the brefofeth gunb'utr that"fit'=fshould-;also' travelnfaihundrd yards or thereab'outsfbefdrearmirigxaf This flirten-i va'lniay be predetermine-dl byprovidihgiialproper relationship-between ithe^speed= of i rotation .fof the' shell-'th'e 'dimensions of cylinder: Seether-,tension onispring 5|'94 anclth/ length'y andi height' ofifiml pel1er739. ,v .7, it;

After the: action; described yiii theicforegoing paragraph, :causes the false; tofA arm; the .Shelli/coni?, tnues fin"V fliglit and',I :the `Lair p in 'fthe tspaoelinside the fuse andl below percussion piston ,isrghiads ually exhaustedgamdvreducedlinfpx'essuren llf--the shell -str-ikeszitsztarget;disc f 3 l atfrthefnose octhe' fuse iis; instantly:` crushed- ?.inL-and strikes :pistonfifli forcing; it Edownvllar.diagairl'-st-.dog e2 iwhich inltm forces, percussion pini |;4 into the prlmer 3 -,\whichj explode'sfthe detonalloltlr:'Ehisifaclon "s-laccelf; erated ybyl :thef' vaclrni'ssiony i ,o :air :.in'to; their-space above. percussioni piston nl l zasi'. the fdiierentialiin. air pressure aboveyand :belewpcthetepiston acts upon its effective areafto force .itfdownwar ,j

If the shell.-missesfitsitarget; -itfcontinues iupf Ward. but: drinngiitsl iightifmercury sescaes' through foricel :4 g graduallyl diminishingfzintvolf-t ume and correspondingly decreasing the upwardr pre'ssure ori-piston :6; whichzpressureiis thus .overcome by the downward pressure'vonl: tl'le' 'pistom caused by; spring* `l 9; ,causingnthetpistoh land'lts rod to descend. 'Ihus lug 25 ofidejiittiisi,

The`

While I have .described my invention 'in .minute detail, especially with reference to a specific embodiment thereof, it is not to b e construed that I am limitedto the design shown in the drawing, for, from the information herein disclosed, a

variety of similar devices could be designed by those skilled in the art without-,departing from the spirit of theinvention as embodiedinlthe following claims. v 1 WhatI claim is:V i 1. A delayed-arming percussion fuse for self exploding projectiles, consisting of a cylinder' mounted axiallyin the fuse,v fluid contained in the cylinder, an orifice in the cylinder wall permitting the "escape of the fluid when the'iluidI is subjected to pressure, a piston movable axially in either direction in the cylinder and acted #upon by pressure of the uid set up vby centrifu- Y gal force; a tubular piston rod fastened tothe f piston and provided with a notch'an'd also provided with a longitudinal slot having an en Iarged opening atoneend; a primary pivoted detent engaging the notch in the'piston rod; a

primer, a primary percussion pink n ormallyre` strained :by the primary detentbut free to move against the said primer' afterrthei detent has` been disengagedfrom the pistonrod and swung,

by centrifugal force acting thereon,. out of they `ieoncentricallyr held withinfthe fuse, ',mercury/` 4 within the cylinder, a `piston within the cylinder land confining the mercuryg-fa piston 'rod attached l A to the piston; a detent engagingv the piston rod` 1 der, vand further adaptedtoibe operated by 'ceri-` 1 y 1, .n

and restrained",lb'y thesaid-'detent untilvthe de-r against theprimerwhen the fusestrikes atar-' path of the primary 'percussion pin; -a plunger arranged to depress the primary percussion pin against its associated primer; a secondary primer and a secondary ring pin adjacent thereto; al

- rod; a spring acting upon thepistbnto forceit #i 'when the fuse and cylinderLarerevolvedg-gthus f 3. A fuse for projectiles vcomprising1.a.cylinder:

and being engaged thereby, t1nes'ai'ii` 'detent being adapted to restrain thepi'ston ffrom i r oving 1, n downwardly toward the head endof' the fcylin` trifugal force ttodisengageitirom thepiston 'downwardlywhen thesaid detent hasbeen disengaged fromthe piston rody'an orifice per,- mittingV dischargeA of thevmercuryll vfrom theV cylinder, a primer, a firing pinadjacent to theprimer v get, and means toY causefthe, mercurytof-rotate f building up hydrostatic vpressure in 'the n iercury` dueA to Icentrifugal 'f orce" and causing the mer- Lcuryto liftl the piston and release the;l de?. tent.'y l s 4. A fuse for projectilescomprising a cylinder 4- concentrically held withinfthe fuse,v mercuryrv within the cylinder, a piston within ther cylinder' and conning .the mercury, "aQpiston rod'aty tached to the piston, Ya detentfengaging .the pisj-l. f. 1 ton rod in such amanner as'simultaneously to ypreventmovement of the piston towardjtheh'ead secondary detent engaging the secondaryxfiring pin and also engaging the slot in the said ktubular piston rod; means to depress the Apiston rod and piston after they have been disengagedfrom the primary detent engaging the notch in the piston rod; means to allow thesecondary detent i to be disengaged from the slot -in the Apiston rod consisting of an enlarged opening in the said slot to permit the detent, when vacted kupon i by centrifugal force, to emerge from the slotyat a predetermined point inthe travel of the said ypiston rod and simultaneously to'fswing `out of.,l

the path of the secondary firing pin, Iand means force lto 'disengage it fromfthefpistonrodi fa.: primer, a iiring` pin adjacent tothe 4primer andi tor depress theiiring pin against the primer to depressjthe said firing pinagainst the sec-l l ondary primer.

2. A delayed-arrning fusefcr projectiles corn-y prising a cylinder mounted axially within the fuse, fluid contained in the cylinder, apiston normally coniining the `iiuicl in the cylinder and-movable in either directionfaxially within the cylinder, atubular piston rod attached to the piston, a notchin the wall of the piston rod, a pivoted detent having' a hook projecting through the notch in the piston rod and engaging the wall thereof, a percussion pinengagedby thedetent when the detent .engages the wall of the piston rod,-but arranged tobe disengaged from the detent when the detent isswung out'- Wardlythrough centrifugal forca-and a vane or impeller disposed 'substantially radially within the cylinder, fixed thereto,fand surrounded by' the fluid, forthe purpose of imparting rotary motion to the fluid when the fuse is rotated;

`thus building vup hydrostatic pressure due to.

- the selfexploding type, comprising: a con'centric piston rod to force the'piston downward inthe snpeiiirnposec1 Online; liquid; a pistoniod at' end-of the cylinder or movement of thev detent away from the pistonv rod until; Ithe piston rod has been moved'in thedirection oppositeto the Y head end of the cylinder,Y the said detent beingl further*v adapted to be* operated by centrifugal' restrained by the said detentunti lthe detent4 5 has been ldisengaged fromfthefpiston rod; means when the fuse'strikesatargetfand mls 159 i cause the mercurytor'otate when the fuse ,and v cylinder v are revolved, thus building uphydro-i static. :pressure due 4to centrifugalv force and causing themercurytoforce the'piston and rod outwardly ofthe cylinder` and to` release the,

irod... 1

` said detentimm engagement `with the PSQFL 1 5. A delayed-arming -fuse frfprojecti'lescylinder,A liquid contair'iedQtherein,fa pistone ,i

ftached tothey .piston a spring acting-upon the cylinder,y ai Vpercussiongpin, ,a detent engaging j `the percussion pin and the piston rodiand are" "7' ,Y ranged to be released therefrom by centrifugal,

'to Y a timingpin, Aa'de'itent engaging the'timingpin and the piston rod and arranged .to be released Atherefromgbyk centrifugalforce when the piston i centrifugal force to .act upon-,the piston and cause it to lmoveoutwaxjdly, disengaging the de' tent; the said vane or impeller being. so proportioned as to impart'- to. thefluid suci'ent hydrostaticpressure due to centrifugal force to raise the piston and'piston rod and Arelease the detent at the end of a givenl period afterthe fuse has been caused to rotate at. a predetermined rate. j

" pressure intherliquid due to centrifugal force,

'force when the piston has'been moved upwardly;

has descended a, predetermined distance inithe"` cylinders/'means fixed within `the `cylinder to` cause rotation .of theliquid when the fuse. and; cylinderiare rotated,v thus creating hydrostatic,y

for the purpose of'liftingthefpiston againstpthe counteracting pressure applied ,by the -spring,;y f

and means to permit ,the escape of thefliquid from the 'cylinder at; a predetermined rate 'tto allowfthe spring to frorcefthe ypiston downward,`

Y ,fdHENRYwsPooNER@f 

